423
FXUS65 KBYZ 201219
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
619 AM MDT SAT JUN 20 2026
KEY MESSAGES
- ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON
THROUGH MONDAY. HIGHEST CHANCES FOR PRECIPITATION EAST OF A
FORSYTH TO SHERIDAN, WY LINE. GUSTY WINDS, SMALL HAIL, AND
HEAVY DOWNPOURS ARE POSSIBLE WITH ANY THUNDERSTORMS THIS
AFTERNOON INTO TONIGHT.
- SEASONAL WEATHER CONDITIONS, WITH LOW CHANCES (10-30%) FOR
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS, EXPECTED FOR
THE REST OF THE WORK WEEK.
DISCUSSION
TODAY THROUGH FRIDAY...
SHORTWAVE TROUGHING CURRENTLY OVER THE PACIFIC NORTHWEST COAST IS
SET TO MOVE INTO THE REGION TODAY THROUGH SUNDAY BRINGING
BENEFICIAL PRECIPITATION TO AREAS OF SOUTHERN MT AND NORTHERN WY.
SOUTHERLY LOW LEVEL FLOW WILL BRING INCREASED ATMOSPHERIC
MOISTURE, INCREASING PRECIPITABLE WATER VALUES TO 1 TO 1.4 INCHES
FOR AREAS BILLINGS EAST. WITH THE LACK OF STRUCTURE AND FORCING
WITH THIS SYSTEM, STORMS WILL BE SLOW MOVING (STORM MOTION OF 5-15
MPH), LEADING TO THE THREAT OF LOCALIZED HEAVY RAIN.
ADDITIONALLY, WITH HI-RES ENSEMBLES GIVING FAR SOUTHEAST MT MUCAPE
VALUES OF AROUND 500-1000 J/KG AND DECENT EFFECTIVE SHEAR VALUES
OF AROUND 40KTS, THE RISK FOR A FEW SEVERE THUNDERSTORMS IS IN
PLACE. THE BEST TIMING FOR THESE STORMS WILL BE MID AFTERNOON
THROUGH AROUND 10 PM MDT. FOR THE REMAINDER OF SOUTHEAST MT, THE
LACK OF SHEAR WILL CAUSE LOCALIZED HEAVY RAIN TO BE THE MAIN
THREAT. USE CAUTION IF RECREATING NEAR ANY BURN SCARS OVER THE
WEEKEND AS CONDITIONS CAN QUICKLY CHANGE WITH BRIEF HEAVY
RAINFALL. PRECIPITATION IS EXPECTED TO BE LIGHTER INTO SUNDAY
AFTERNOON AND EVENING AS WEAK SUBSIDENCE SLIGHTLY DRIES THE
ATMOSPHERE. ADDITIONAL PRECIPITATION IS EXPECTED FOR THE SAME
AREAS OF SOUTHEAST MT WITH A FEW STRONG THUNDERSTORMS POSSIBLE
MONDAY AFTERNOON AND EVENING. AS FAR AS AMOUNTS GO, AREAS ROSEBUD
COUNTY AND SHERIDAN COUNTY, WY EAST HAVE ABOUT A 50-80% CHANCE OF
GETTING AT LEAST A HALF INCH OF PRECIPITATION SATURDAY EVENING
THROUGH MONDAY EVENING. KEEP IN MIND LOCALLY HIGHER AMOUNTS ARE
POSSIBLE UNDER THUNDERSTORMS OR AREAS OF LOCALIZED STRONGER
FORCING. BY LATE MONDAY INTO TUESDAY, HIGHER HEIGHTS MOVE IN
BEHIND THE LOW, DECREASING THE CHANCE FOR PRECIPITATION. ENSEMBLES
LOOK TO KEEP UNSTABLE NORTHWEST FLOW OR BRIEF RIDGING BEFORE
POTENTIAL PACIFIC TROUGHING AT THE END OF THE WEEK. TEMPERATURES
THROUGH THE PERIOD WILL REMAIN SEASONAL IN THE 70S TO LOW 80S,
INCREASING INTO THE UPPER 80S FOR THE SECOND HALF OF NEXT WEEK. TS
AVIATION
VFR CONDITIONS WILL PREVAIL INTO THIS AFTERNOON FOR MOST AREAS.
CLOUDS INCREASE TODAY AS A DISTURBANCE LIFTS INTO THE REGION
BRINGING SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO
TONIGHT, DEVELOPING OVER THE MOUNTAINS AND MOVING EAST THROUGH THE
AREA. THE MAIN HAZARDS WITH ANY THUNDERSTORM IS HEAVY RAIN
REDUCING VISIBILITY, SUDDEN GUSTY WINDS, AND SMALL HAIL. MVFR TO
IFR CONDITIONS ARE POSSIBLE WITH THE STRONGEST SHOWER/THUNDERSTORM
ACTIVITY.
POTENTIAL TS TIMING:
KLVM: 18-03Z
KBIL: 21-04Z
KSHR: 21-06Z
KMLS: 02-09Z
STP
PRELIMINARY POINT TEMP/POPS
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 077 057/079 053/072 049/076 051/082 055/086 057/092
2/T 42/B 45/T 10/U 00/B 11/U 21/B
LVM 073 048/077 045/072 041/077 044/083 048/086 050/089
6/T 51/U 34/T 10/U 01/U 22/T 11/B
HDN 079 055/078 050/072 046/075 048/081 052/086 055/092
3/T 62/B 47/T 10/U 01/B 11/U 21/B
MLS 080 055/073 050/070 048/072 047/076 051/081 054/087
1/B 67/T 37/T 11/U 00/B 02/T 11/B
4BQ 079 055/072 050/069 047/071 047/075 051/080 054/087
4/T 99/T 39/T 30/U 01/B 12/T 21/B
BHK 076 050/067 046/069 043/069 042/073 046/077 050/083
1/N 69/T 28/T 32/W 00/B 01/U 21/B
SHR 078 050/074 046/066 042/072 044/078 048/082 049/087
5/T 87/T 69/T 31/U 13/T 24/T 22/T
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page